Method of cleansing and/or sterilizing the filler tube in packaging machines

ABSTRACT

A method of washing, i.e. cleansing and/or sterilizing a packaging machine filler tube by closing one end of the tubular packaging material to form a closed space around the filler tube, introducing a liquid washing agent into the space thus formed and then heating the agent.

United States Patent [72] Inventors Alex'luma Appl. No. Filed Patented Assignee Priority METHOD OF CLEANSING AND/0R STERILIZING THE FILLER TUBE IN PACKAGING MACHINES Primary Examiner-Morris O. Wolk Assistant Examiner--D. G. Millman Attorney-Pierce, Scheffler & Parker 7 Chins 2 Drum; Figs ABSTRACT: A method of washing, i.e. cleansing and/or U.S. Cl 134/24, sterilizing a packaging machine filler tube by closing one end 21/58, 21/91, 141/91 1 of the tubular packaging material to form a closed space Int. Cl. B08b 3/10, around the filler tube, introducing a liquid washing agent into i A A 6 1Ll /Q0 the space thus formed and then heating the agent.

| l r I l l i 4 I I f .7 f

,%j I v PATENTEUum 26 I97! SHEET 10! 2 Fig.1

PATENTEUnm 26 Ian sum 2 OF 2 METHOD OF CLEANSING AND/OR STERILIZING THE FILLER TUBE IN PACKAGING MACHINES This invention is related to packaging technology and is concerned with a method of, and equipment for, cleansing and/or sterilizing the filler tube in packaging machines of the kind which form a packaging tube around the filler tube, and where the packaging tube, while partially filled with the liquid to be contained in the packages, is divided into filled and sealed packages at the same time as the column of liquid in the packaging tube is also divided.

The demand for a sterile packaging process, particularly in connection with the packaging of goods such as milk which offer a conducive environment for bacteria, has been increasing. These demands have been further accentuated in connection with aseptic packaging of sterile liquids, and a number of methods have therefore been proposed for bringing about satisfactory aseptic conditions when such goods are being packaged. One method e.g. aims at sterilizing the inside of the filler tube, and the method is used for filler tubes where there is a possibility of circulating the cleansing agent. With these filler tubes, circulation washing and sterilization are carried out right down to a baseplate attached to the opening of the tiller tube during the washing operation.

One aim of this invention is therefore to supplement such a sterile washing process by cleansing and sterilizing the outside of the tiller tube as well. This aim has been achieved by this invention, which is characterized by the lower end of the packaging tube being closed by a device, whereby the packaging tube and the device together define a space which is supplied with a cleansing and/or sterilizing agent through a duct in the device, at least up to that level which the liquid surrounding the filler tube reaches while the packaging machine is in operation, after which the cleansing and/or sterilizing agent is heated to a suitable cleansing and sterilizing temperature.

In order to clarify still further the subject matter of the invention, it may be mentioned that in packaging machines of the above kind the liquid is introduced into the packaging tube below the liquid level, and there is therefore great danger that some of the liquid will be left behind on the outside of the filler tube. This danger is particularly great when operation of the machine is stopped either temporarily or for the day. In either case, the outside of the filler tube, where one or perhaps several individual micro-organisms may find good conditions for growth in the substrate, is a potential source of contamination unless measures are taken, on the one hand, to prevent adhesion of the substrate to the outside of the tiller tube and, on the other, to ensure that any organisms there may be present will not survive. It may be mentioned further that the packaging tube is made use of during cleansing and sterilization of the outside of the filler tube, to form the walls of a container for the reception of the cleansing, sterilizing and rinsing agents. 7

There are a number of advantages in cleansing and/or sterilizing the outside of the filler tube by the method specified in the invention, as compared with processes used earlier. The method is thus simpler and requires less time than if washing were carried out manually, since there is no need to remove and to dismantle the apparatus. Aseptic conditions are in addition maintained when the method in accordance with the invention is used in the event of a breakdown in operation or when work is finished. A further advantage is that only the area actually exposed to danger is sterilized, which means, among other things, that parts of the machine which do not have to be subjected to such harsh treatment will not become overheated or be exposed to chemical attack, and it is further possible to carry out this cleansing and/or sterilization simultaneousiy with the cleansing and/or sterilization processes of the milk sterilizer or other components used in conjunction with the sterile filling operation.

The invention is also concerned with equipment to be used for carrying out the method specified, the equipment being I characterized by a supporting arrangement designed to be fitted around a packaging tube, and by a device designed to be introduced into the packaging tube, whereby the device consists of a plate, disc or similar component having a. a sealing strip around its periphery, the sealing strip being designed to form a liquidtight seal against the inside of the packaging tube, I

b. a combined supply and drainage duct for the cleansing and/or sterilizing agent,

c. piping connected to the combined supply and drainage duct for the supply of the cleansing and/or sterilizing agent into the space defined by the inner sidewalls of the device and of the packaging tube, and to remove it therefrom,

d. surfaces on the inner sidewall which slope towards the combined supply and drainage duct, and

e. a heating coil designed to heat the cleansing and/or sterilizing agent.

Further advantages and objects of the invention will be apparent from the following description of the invention, reference being made to the attached diagrammatic drawings, of which FIG. 1 shows, in partial cross section, equipment for carrying out the method in accordance with the invention, and

FIG. 2 shows also partially in cross section, a part of the equipment depicted in FIG. I, to an enlarged scale.

Reference I in FIG. I denotes a packaging tube which consists of paper, aluminum or a plastic material, or a combination of these materials, and which has been formed around a filler tube 2 designed to introduce liquid into the tube I. Reference 3 denotes a plate which has a sealing arrangement 4 around its periphery. There is furthermore a combined filling and drainage hole in the plate 3 for the cleansing and/or sterilizing agent which is supplied through the piping 9. The plate 3 also has a heating coil 10 with inlet and outlet pipes II and 12 respectively. The plate 3 and its sealing arrangement 4 are designed to form a liquidtight seal in the packaging tube I, whereby the plate 3 and the packaging tube 1 will form a container 13 for the cleansing and/or sterilization process.

The plate and its attachments, as well as their working will now be described more closely by reference to FIG. 2. The plate 3, as has been mentioned before, has a sealing arrangement 4 which is designed to form a liquidtight seal in the packaging tube I. The sealing arrangement consists of a sealing strip 5 and a supporting unit or presure ring 6 which surrounds and is in contact with the tube I opposite the circumference of said strip. The sealing strip 5 consists at least partly of material that can be deformed, such as rubber, and may in its simplest version consist of a hose, a pipe vulcanized into a hose, or similar. As may be seen on the Figure, the sealing strip 5 is seated in a groove at the peripheral edge of the plate 3. The sealing strip 5 is furthermore connected to a tube 7 which is intended to convey to the inside of the sealing strip a pressurized agent, e.g. a gas under pressure such as compressed air. One of the functions of the pressure ring 6, which is fitted around the free portion of the sealing strip 5, is to shape the sealing ring and to prevent its deformation in the radial direction. The plate 3 is intended to be introduced into the packaging tube in such a way that the sealing strip 5 will be inside the tube and the pressure ring 6 outside the tube at the same level as the strip. When the sealing strip 5 is subjected to pressure by the introduction of a pressurized agent through the pressure hose 7, the sealing strip will exert pressure against the inside of the packaging tube, which pressure and the area under pressure, or in other words the sealing surface, will be caused to increase owing to the action against the pressure ring 6. The sealing procedure may be described in other words by saying that the wall of the packaging tube 1 is clamped between the sealing strip 5 and the pressure ring 6, such clamping being the result of pressure from inside the tube (toward its inside surface and) radially outwards. The upper side of the plate 3 which faces the lower end of the filler tube 2 should preferably have a somewhat conical or concave shape sloping towards the combined filling and drainage hole 8 for the cleansing and/or sterilizing agent in the plate 3, The piping 9 is connected to the hole 8 which should preferably be situated at the center of the plate 3, and functions to supply the cleansing and/or sterilizing agent to the space 13 above and defined by the plate 3 and the packaging tube, and to remove it therefrom. The plate 3 also supports the heating coil 10, in the shape of e.g. a helix, which is intended for heating the cleansing and/or sterilizing agent introduced into the space 13. The heating coil 10 is located adjacent the conical sideof the plate 3 and is arranged so as to surround the lower end of the filler tube 2. The .heating coil 10 is also connected to inlet and outlet pipes 11 and 12 respectively which pass through the plate 3. The inlet and outlet pipes 11 and 12 respectively are fitted with surrounding handles 14 and 15 and the outlet pipe 12 may in addition be fitted with a steam trap 16 when the heating medium is superheated steam. The heating coil 10 may naturally be designed to be heated in another way, e.g. electrically.

The method of operation of the above equipment will now be described, the expression cleansing and/or sterilizing agent used. heretofore being replaced by the term washing agent" which is intended hereinafter and in the appended claims to refer to a cleansing agent, a sterilizing agent or a combination thereof.

When the outside of the filler tube 2 is to be cleansed and/or sterilized, the plate 3 is fitted into the free end of the packaging tube 1 which has been obtained by tearing off orin some similar way, care being taken at the same time that the tube material is inserted between the sealing strip of the plate 3 and the pressure ring 6. The plate 3 is furthermore inserted into the tube 1 in such a way that the heating coil is situated around the lower outlet end of the fillertube 2. in order to retain the plate 3 in the tube 1, a pressurized agent such as compressed air is admitted through the pressure hose 7, whereby the sealing strip 5 is pressed against the inside of the packaging tube 1 and against the pressure ring 6 situated outside the tube 1. This operation at the same time produces a liquidtight seal between the plate 3 and the packaging tube 1, the seal being accomplished from the inside of the tube 1 radially outwards. A well-defined space 13 or is thus obtained for the cleansing, sterilizing and rinsing agents, the space 13 being bounded by the plate 3 and the packaging tube 1. Washing agent is then introduced into the circumscribed space .13 through the washing agent pipe 9. The washing agent is admitted into the space 13 up to a level 18 such that the washing agent surrounds the filler tube 2 to a level higher than that of the liquid contained in the packages when the machine is in operation. The washing agent is then heated to boiling tem perature with the aid of the heating coil 10, during which operation the washing agent is caused to circulate in the space 13 so that even such parts thatare difficult to cleanse will be efi'rciently cleansed. After some time, when the cleansed or sterilized parts have been freed from particles of impurity and the like, the space 13 is cleared of washing agent through the piping 9 affixed to the plate 3. The space 13 may in the end be rinsed if desired by e.g. sterile hot water also introduced and drained away through the washing agent pipe 9. A filler pipe with a sterile outer surface will thus be obtained by the method of operation described above.

When the machine ceases to portion out liquid, e.g. overnight, the plate 3 and its ancillary equipment are fitted into the packaging tube 1 and are made to form a seal against the tube wall, after which at least one cleansing of the apparatus is carried out with a view to removing liquid that has been left behind. Before the machine is started up again, e.g. the next morning, another cleansing operation may be carried out if desired, but the apparatus must be sterilized at least once this time, as described above. When this has been done, the pressure in the sealing strip 5 of the plate 3 is released, so that the plate may be removed from the packaging tube 1 and put to the side, after which the machine may be started up. The apparatus is to be used invthe way described even when the machine is out of action for a short time. A cleansing and sterilizing operation using the above method and equipment may be carried out at any time when the machine is out of ac tion.

in a test series using the equipment and the method specified in the invention, milk suspension containing spores of Bacillus subtilis as the contaminating agent, and a 2 percent caustic soda (NaOH) solution as the washing agent, were used.

During .the tests, the 2 percent caustic soda solution was heated by the heating coil 10 which consisted of coppertubing. Steam, having a temperature of 145 C. (293 F.) and maintained at a pressure of 4 atm. .(59 p.s.i.g.,) was continuously supplied to the heating coil 10 through the inlet pipe 1-1. The steam was exhausted through the outlet pipe 12 and had atmospheric pressure and a temperature of approximately C. (212 F.) beyond thesteam trap 16. After the washing operation, which went on for 10 minutes, the filler tube 2 was rinsed using sterile distilled water at room temperature, in order to neutralizeany caustic soda solution left behind. The filler tube .was then swabbed with beef-tea that had been inc'u bated for 7 days at a temperature of 30C. (86 F.), and checks were then made'to find out if-growth had taken place.

It was found that the equipment and the method specified in the invention lend themselves well to removal of all substrate particles remaining on the outside of the filler tube, and to sterilization of the outside of the filler tube, withoutthis hav; ing to be dismantled'for manual cleansingand decontamination. It was further established, by carrying out a number ot' test series, and varying the washing period, that sterility ,was

attained with a sufficient margin of safety when a washing period of 10 minutes was used.

It is naturally possible, within the framework of the ideaunderlying the invention, to modify both the equipment described and the method of cleansing and sterilizing the outside of the filler tube. The pressure ring may thus be attached to the plate,-by making it in the shape of a U so that its legs reach round the lower free end of the packaging tube. The sealing strip may also consist of several parts, one of these parts being that capable of deformation which .will constitute the means'of accomplishing the seal. Thereis no need for the plate to be solid; it may for instance consist of two discs situated at acertain distance from one another, the sealing strip being clamped between these discs. The inletand outlet pipes for the heating coil may be situated next to one another so that they. can be fitted with a common handle. 5

We claim:

1. A method of washing the .filler tube in packaging machines of'the kind which form a packaging tube 1) around the filler tube (2) and where the packaging tube, while partially filled with the liquid tobe contained in the packages, is divided into filled and sealed packages, at the same time as the column of liquid in the packaging tube is also divided, characterized by the lower end of the packaging-tube) below the end of the filling tube (2) .being closed by a device ('3) whereby the packaging tube and the device togetherdefine a space (13) which is supplied with a washing agent through a duct (8) in the device (3), at least up to that level (17) which the liquid surrounding the filler tube reaches while the packagingmachine is in operation, after which the washing agent is heated to a suitable washing temperature.

2. A method in accordance with claim 1, characterized by the device (3) forming a liquidtight seal against the packaging tube (1) by means of a sealing strip (5) which, under the influence of a pressurized gas, is pressed against the inside of the packaging tube so as to form a liquidtight seal, whereby a supporting arrangement (6) on the outside of the'packaging tube limits the expansion of the sealing strip (5) in the radial direction of the device (3).

3. A method in accgrdance with claim 1, characterized by the heating of the washing agent being accomplished by means of a heating coil (10) through which steam flows.

4. A method in accordance with claim 1, characterized by the heating of the washing agent being accomplished electrically by means of a heating coil of electrically resistant material.

5. A method in accordance with claim 1, characterized by the washing agent consisting of a cleansing of caustic soda (NaOH).

6. A method in accordance with claim 1 wherein the washing agent comprises a cleansing agent.

7. A method according to claim 1 wherein the washing agent comprises a sterilizing agent.

t t i t i 5 

2. A method in accordance with claim 1, characterized by the device (3) forming a liquidtight seal against the packaging tube (1) by means of a sealing strip (5) which, under the influence of a pressurized gas, is pressed against the inside of the packaging tube so as to form a liquidtight seal, whereby a supporting arrangement (6) on the outside of the packaging tube limits the expansion of the sealing strip (5) in the radial direction of the device (3).
 3. A method in accordance with claim 1, characterized by the heating of the washing agent being accomplished by means of a heating coil (10) through which steam flows.
 4. A method in accordance with claim 1, characterized by the heating of the washing agent being accomplished electrically by means of a heating coil of electrically resistant material.
 5. A method in accordance with claim 1, characterized by the washing agent consisting of a cleansing solution of caustic soda (NaOH).
 6. A method in accordance with claim 1 wherein the washing agent comprises a cleansing agent.
 7. A method according to claim 1 wherein the washing agent comprises a sterilizing agent. 